1. Field of the Invention
The present invention relates to a spindle motor and a disk drive apparatus.
2. Description of the Related Art
A disk drive apparatus, such as a hard disk drive, is known. A spindle motor arranged to rotate a disk is installed in the disk drive apparatus. A known disk drive apparatus is described, for example, in JP-A 2012-005339. The disk drive apparatus described in JP-A 2012-005339 includes a base arranged to support primary components of a motor (paragraph [0031] and FIG. 1 of JP-A 2012-005339).
In recent years, there has been an increasing demand for slim notebook PCs and tablet PCs. There has accordingly been a demand for a further reduction in the thickness of disk drive apparatuses installed in these PCs. Regarding the motor described in JP-A 2012-005339, for example, a reduction in the thickness of the disk drive apparatus can be achieved by reducing the axial thickness of a base plate arranged to support the motor.
However, a reduction in the axial thickness of the base plate results in a decrease in rigidity of the base plate. The decrease in the rigidity of the base plate, for example, increases the likelihood that a vibration or noise accompanying drive of the motor will occur. The vibration accompanying the drive of the motor causes a vibration of a disk, which may increase the likelihood that an error in reading and writing of data will occur.